The present invention is related generally to remotely controllable sensors and more specifically to a mechanical delivery system for remotely positioning a contacttype ultrasonic sensor for inspecting components within a nuclear reactor.
The use of contact-type ultrasonic sensors is well-known for the inspection of mechanical components. It is also well-known to use remotely controllable delivery systems for positioning the ultrasonic sensor when manual positioning is not possible, i.e., because of space limitations, hostile environments, etc. However, certain environments, such as inside a nuclear reactor, present unique problems.
Typically, inspection of components within a nuclear reactor is necessary to gather data on operational performance, detect failures, comply with regulations or the like. Inspections typically occur during a scheduled outage for refueling or routine maintenance. Such outages are kept at minimal length for economic reasons. Thus, because of the short duration of the outage, it is necessary to perform a large number of complex inspections in a very short time.
In addition to the time constraints, the inspections must be performed from a platform above the nuclear reactor such that distances of thirty or even forty feet are not uncommon between the operator and the device being inspected. Further, the component to be inspected may have a notch or recess into which the ultrasonic sensor must be positioned. Thus, a specific orientation between the sensor and the component to be inspected must be achieved before the sensor can be inserted into the notch or recess. Attempts at inserting the sensor before the proper orientation is achieved may result in damage to the sensor. Damage to the sensors may also occur if the sensors collide with obstacles on the way to or from the component to be inspected.
Considering the complexity of a nuclear reactor, the large number of inspections which must be made in a short time, and the difficulty of the "blind38 positioning of a fragile sensor from a position forty feet away from the operator in a radioactive underwater environment, it is clear that the development of mechanical systems for remotely positioning the sensors presents a wide variety of challenges to the design engineer.